The present invention relates to the field of security systems for monitoring and controlling access to a secured or access restricted area, such as a vehicle or house.
Security systems are in wide use today to control and/or monitor access to secured or access-restricted areas. Such systems typically employ one or more sensors and/or trigger switches which are monitored or controlled by a central controller to sense intrusion or to allow controlled access. Examples of such systems include vehicle security systems and building security systems, which may be activated by either a remote switch or transmitter or by a key pad to enter a predetermined code. Entrance of the correct code typically arms or disarms the system opens or closes a door or the like. Automotive security systems typically employ vibration sensors, glass breakage sensors, ultrasonic or microwave sensors, as well as triggers such as door, hood or trunk triggers, to detect unauthorized intrusion attempts and to activate alarm devices such as sirens or lights to warn off the intruder and call attention to the intrusion, and in most cases such system will also activate a relay or other electronic circuits disabling the vehicle ignition system.
The sensors and triggers typically detect attempts to intrude into the protected area, such as by way of a door or window, forcing a hood or trunk open, lifting or moving the vehicle or the like. The trigger devices may take the form of switches which are activated by the opening or closing of a door or window. To allow access through doors or other access points, devices which release or position locking elements, such as solenoid switches, are typically employed.
Conventional security systems will not arm when a sensor indicates that a door or window is open, or when a sensor indicates that there is presently an intrusion into the protected area. As an example, a vehicle door left open will typically prevent the security system from being armed, or a window left open in a building will prevent the building security system from being armed. For the same reason, a defective sensor which indicates that a door is open irrespective of the position of the door, i.e., open or closed, will also prevent the security system from being armed. The result is that the vehicle or building owner is deprived completely of the benefit of the security system until the defective sensor is repaired.
Many vehicle security systems are added to the vehicle after manufacture of the vehicle by independent accessory dealers and the like. Proper installation is necessary to ensure proper operation of the security system and prevent damage to the system components, particularly those components carrying significant current levels. Most of the security systems on the market today are controlled by electronic digital logic circuits, which control relays or electronic switching elements such as output transistors which provide power to the alarm siren and the ignition or starter cutoff relay. If during installation or as a result of improper installation procedures, the switching elements are connected improperly, the switching elements can be shorted out and destroyed due to excessive current flow. This will result in return of the entire unit to the manufacturer, resulting in repair or replacement expense.
Another disadvantage of conventional security systems is repetitive alarm alerts due to conditions such as a defective sensor, or noncorrected or ignored intrusion events. Most systems on the market have a maximum alarm duration for sounding a siren or other noise-making device when an alarm event is detected, after which duration the alarm resets itself. The maximum duration is typically set by local ordinances requiring that alarms shut off after some fixed time, say ten minutes, regardless of whether the owner has attended to the alarm or not. However, if the alarm was caused by a sensor or trigger which remains in an active state after the alarm system resets itself, then successive alarm cycles will be repeated over and over again until the alarm is disabled or the car's battery is depleted.
Another typical case of repeated false alarms occurs when the vehicle is parked in a location having high ambient vibration levels and the system vibration sensor is repeated activated by these vibration levels. These false alarms diminish the effectiveness of the alarm system, and cause substantial noise pollution.
A further limitation of conventional vehicle security alarm systems is that they typically provide only a single type of audio alarm signal, such as a siren, or a siren sound alternating with a voice-synthesized audio message, e.g., "BURGLAR-BURGLAR." The same audio alert signal is generated no matter why the alarm condition was declared, e.g., a door opening results in the same alarm signal as a vibration sensor alarm condition. In many cases where the sensors cause an alarm, such as a vibration sensor or glass breakage sensor, a real intrusion event follows the sensor alarm condition within a few moments by the thief gaining entry through a door, trunk or hood. Yet because the same alarm audio signal results from both the sensor alarm and the door trigger alarm, the user may simply assume that the sensor alarm has caused the second alarm, not an actual intrusion into the vehicle, and ignore the warning.
Many conventional vehicle security systems provide the capability of not only activating the alarm siren when an alarm event is detected, but also turn the vehicle interior light on during the alarm cycle duration. It would be advantageous to control the interior light in such a manner as to draw even more attention to the vehicle and to disrupt intrusion activities.
Most vehicle security systems on the market today can be actively armed by the user with a remote transmitter device, or alternatively will automatically arm itself some predetermined delay after the door of the vehicle is closed. The former arming alternative will be described herein as "active arming," and the latter arming alternative as "passive arming." It is common in the installation of vehicle security systems for the system door trigger line to be wired from the vehicle interior light system. Thus, the system looks to the status of the interior light to determine the open/closed status of the vehicle doors. This is done for the convenience of the installer who can more quickly wire to the interior light than to the door switches. This leads to a problem for vehicles which have an interval timer on the interior light, so that the light remains on for some fixed time after the doors are closed as a convenience feature. If the conventional security system were to be actively armed by the remote transmitter after the doors are closed but while the interior light remains on during the interval timeout, the system will interpret the active interior light as a signal that the doors are open, and will either refuse to arm, or automatically trigger an alarm. To remedy this problem in conventional systems, the controller ignores the door trigger state for a fixed time interval. However, since different cars have different "on" time intervals for the interior light, conventional systems must have a fixed long time interval to allow for the longest "on" time interval among all car models. Since the security system provides no protection to the vehicle during this time interval, it leaves an opportunity for a vandal or thief to gain access to the vehicle.
In regard to passive arming, whenever the alarm is armed passively, the vehicle security systems typically allow for a short entrance delay after opening the vehicle door before an alarm is sounded. This entrance delay allows the user to manually disarm the system, perhaps by turning on the ignition, entering a code in the keypad or by some other action which is performed within the vehicle. This delay is also desirable with remote-controlled systems, for the inevitable case when the user has lost or forgotten his transmitter, or when it has malfunctioned. However, thieves may use the entrance delay to their advantage. For example, entrance may typically be gained by breaking a window; the vibration sensor and/or glass breakage sensor will trip the alarm, and sound the audio alert signal. The thief may simply leave the scene until that alarm signal has ended. If no one has investigated the alarm, the thief is free to enter the vehicle through the door, and the alarm will not immediately be activated due to the entrance delay. The thief has the benefit of the entrance delay time interval, which is typically on the order of over fifteen seconds, allowing him to either disable the alarm system, or even more commonly, to "hot wire" the ignition, thereby starting the engine.
Many luxury automobiles are equipped with power door locks. Some electronic security and control systems have been integrated with the power door locks so as to automatically lock the doors when the security system is actively armed, and to automatically unlock the doors when the system is disarmed For systems having a passive arming feature as described above, however, automatic control over the door locking function can create problems. The passive arming of the system can result in the user becoming inadvertently locked out of his vehicle, say if he forgets to remove his key from the ignition when fueling his car or if he forgets to take his remote transmitter with him. Once the door is shut the system will automatically arm itself and lock the doors, if that feature is tied indiscriminately to system arming. As a result, conventional systems have sometimes not provided automatic door locking when the system passively arms itself. While such a solution eliminates the possibility of the user accidently being locked out of his car, security of the vehicle is diminished when the user would want the doors locked, unless he manually locks the doors.
There are several known techniques by which the user may interface with the security system. One is by way of a remote transmitter Another is by way of a keypad mounted within the vehicle, for example. Commonly, a system having a remote transmitter for arming and disarming the system does not also employ a keypad, which would add to the expense of the system and also invite tampering with the system. Instead such a system may use a multiposition switch say a three position switch, mounted within the vehicle for allowing user interface for purposes other than arming and disarming the system. Thus, the switch may be employed for programming information regarding features provided by the system. If there are many possible features to be programmed, say ten to twenty, then the convenience of the programming function is limited by the data entry means, i.e., a single switch element. Relatively complex coding and programming sequences may be required, leading to difficulty in programming a desired function particularly when the user only infrequently programs the system.
Conventional vehicle security systems may have certain features which may be enabled or disabled for a particular application. However, the system installer is the one who enables or disables the features, e.g., by cutting wires, grounding pins, and the like. The user does not have the ready capability of enabling or disabling features of the system. This does not permit the flexibility of conveniently reconfiguring the system features to customize the system for a particular application.
It is therefore an object of the present invention to provide a security system whose high current output circuits are protected against destructive high current levels caused by miswiring or missed connections.
A further object of the invention is to provide a system which does not repetitively cycle through alarm cycles due to a constantly active sensor or trigger device.
An additional object of the invention to provide a security system which provides a different type of alarm signal when a door is opened than when a sensor alarm condition is sounded.
Another object of the invention is to provide a means of immediately actively arming the security system on vehicles equipped with an interior light delay timer, allowing the system to be fully armed as soon as the interior light is turned off.
Another object of the invention to provide a security system which provides the convenience of an entrance delay feature yet automatically eliminates the entrance delay after a sensor is activated.
Still another object of the invention is to provide a vehicle security system having a passive arming feature with an intelligent automatic locking and relocking function, whereby the user gains the benefit of integrating the door locking function with the security system yet does not suffer the disadvantage of increased risk of locking the vehicle inadvertently.
Another object of the invention is to provide an means of adding or deleting features of a security system through a remote transmitter and a simple switch element.
A further object of the invention is to provide a user-programmable vehicle security system wherein the user can conveniently program the system to enable or disable system features without the use of tools and without rewiring the system.